Lentigines Including Lentigo Simplex, Reticulated Lentigo and Actinic Lentigo V.3 Paolo Carli and Camilla Salvini

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Chapter V.3 Lentigines Including Lentigo Simplex, Reticulated Lentigo and Actinic Lentigo V.3 Paolo Carli and Camilla Salvini

Contents V.3.1 Simple Lentigo

V.3.1 Simple Lentigo...... 290 The definition of lentigo simplex (or lentigo V.3.1.1 Definition ...... 290 simplex) is a common brown melanocytic le- V.3.1.2 Clinical Features ...... 290 sion, considered to be the precursor of junction- V.3.1.3 Dermoscopic Criteria...... 291 al melanocytic nevi. V.3.1.4 Relevant Clinical Differential Diagnosis...... 291 V.3.1.5 Histopathology...... 291 V.3.1.6 Management...... 292 V.3.1.1 Definition V.3.2 Ink-Spot Lentigo ...... 292 Lentigines are macular increases in melanin V.3.2.1 Definition ...... 292 pigmentation of the skin that are persistently V.3.2.2 Clinical Features ...... 292 present. Histopathologically, they show an in- V.3.2.3 Dermoscopic Criteria...... 292 crease in the number of melanocytes at the der- V.3.2.4 Relevant Clinical Differential mo-epidermal junction. Lentigines can be clas- Diagnosis...... 292 sified in accordance with aetiological factors V.3.2.5 Histopathology...... 293 (Table V.3.1). V.3.2.6 Management...... 293 V.3.3 Actinic Lentigo...... 293 V.3.3.1 Definition ...... 293 V.3.1.2 Clinical Features V.3.3.2 Clinical Features ...... 293 Macular area of light-brown or brown-black V.3.3.3 Dermoscopic Criteria...... 293 pigmentation, fairly uniform, usually circu- V.3.3.4 Relevant Clinical Differential lar or oval, with 3–5 mm in diameter, although Diagnosis...... 293 several individual lentigines may coalesce V.3.3.5 Histopathology...... 294 (Fig. V.3.1). Lentigines may occur in any area of V.3.3.6 Management...... 294 the skin, the muco-cutaneous junctions or the References...... 294 conjunctive. They are very common, particu- larly in persons with red hair and skin type I– II. V.3 Chapter V.3 Lentigines Chapter V.3 291 Lentigines Including Lentigo Simplex, Table V.3.1. Classification of lentigines Lentigines associated Lentigines not associated Lentigines as characteristic Reticulated Lentigo and Actinic Lentigo V.3 with excessive exposure with excessive exposure feature of multisystem to UV radiation to UV radiation syndromes Paolo Carli and Camilla Salvini Lentigo simplex (juvenile lentigo) Genital lentiginosis Centrofacial lentiginosis Reticular lentigo (ink-spot lentigo) Labial lentigo LEOPARD syndrome (or multiple lentigines syndrome) Actinic (solar) lentigo Oral lentiginosis Laugier−Hunzinger syndrome Photochemotherapy (PUVA) lentigo Peutz−Jeghers syndrome Sunbeds lentigo Cardiac myoma syndrome

Fig. V.3.1. Lentigo simplex (clinical photo) Fig. V.3.2. Lentigo simplex (dermoscopic photo)

V.3.1.3 Dermoscopic Criteria V.3.1.5 Histopathology On dermoscopy, lentigo simplex appears with a There is a linear increase in the number of me- typical brown or brown-black network, with lanocytes along the dermo-epidermal junction thin pattern and uniformly arranged stitches without melanocytes in the dermis. The in- (Fig. V.3.2). This profile is due to the elongated creased pigmentation is due both to melanin in and hyperpigmented epidermal ridges [1]. the epidermis and stratum corneum, and to the presence of melanophages in the papillary dermis. The papillary and interpapillary ridges are V.3.1.4 Relevant Clinical Differential usually elongated. Diagnosis Lentigines are distinguished from ephelides by the fact that they have no connection with sun- light: they do not darken or increase in number upon sun exposure. 292 P. Carli, C. Salvini

V.3.1.6 Management As they have no increased risk for malignancy than common nevi, the patient should be reas- sured. Laser therapy may be effective if the patient requests treatment for aesthetic reasons.

V.3.2 Ink-Spot Lentigo V.3.2.1 Definition

The ink-spot lentigo or reticulated lentigo (reticulated black solar lentigo, reticular lentigo, acquired reticulated lentigo, reticulated mela- Fig. V.3.3. Reticulated lentigo (clinical image) notic macule) is a small (<5 mm in diameter) black macula, usually on sun-exposed areas. It occurs more frequently in adult men, and the most involved sites are chest and upper back [2]. It is a rare variant of lentigo, which is particu- larly important because clinically it may be con- fused with melanoma in situ.

V.3.2.2 Clinical Features It is a brown-black lesion with a wiry or bead- ed appearance and a markedly irregular outline (Fig. V.3.3). The lesion is limited to sun-exposed areas of the body and it is usually solitary with near numerous solar lentigines. It affects mainly fair-skinned individuals with skin types I and II. Fig. V.3.4. Reticulated lentigo (dermoscopic image)

V.3.2.3 Dermoscopic Criteria V.3.2.4 Relevant Clinical Differential Diagnosis Although ink-spot lentigo may be a cause of concern for both doctor and patient, due to its black pigmentation, dermoscopic examination Because of its dark colour and irregular border, shows a peculiar pattern of benignity; therefore, the ink-spot lentigo is often considered to be V.3 in the majority of cases, dermoscopy enables the suspicious for melanoma; however, the clinically clinician to achieve a correct non-invasive clas- and dermoscopically special pathognomonic sification of this lesion without the need of veri- features allow to make the diagnosis of a benign fication biopsy. Dermoscopic features are those lentigo. of a peculiar type of prominent (black to dark brown), broken-up network, which allows im- mediate diagnosis of ink spot lentigo (Fig. V.3.4) [3]. Lentigines Chapter V.3 293

V.3.2.5 Histopathology The histopathology of the lesion shows lentigi- nous hyperplasia of the epidermis, very marked basal cell hyperpigmentation, rete-tip accentua- tion and characteristic acromic skip areas. The melanocytes, without cytological atypia, may be normal or minimally increased in number.

V.3.2.6 Management The lesion is completely benign (although the features may sometimes be clinically worri- Fig. V.3.5. Actinic lentigo of the hand some) and no treatment is required.

V.3.3 Actinic Lentigo V.3.3.1 Definition

Actinic lentigo (or solar lentigo or lentigo senilis or senile freckle or liver spot) is characterized clinically by a macular and tan-coloured lesion arising on sun-exposed sites, usually larger than 6 mm in size and with striking irregular bor- ders. Histologically, it is classified as early seborrhoeic keratoses.

Fig. V.3.6. Actinic lentigo (dermoscopic image) V.3.3.2 Clinical Features Actinic lentigines are benign, irregular macula like” edge. On the face dermoscopy reveals spe- and vary from light to dark brown in colour cific criteria according to the particular histo- (Fig. V.3.5). Their size is variable from 0.1 to logical architecture shown by sun-damaged 1 cm or more in diameter and they have a ten- skin. The pigmentation gives rise to a diffuse dency to coalesce. They are associated with cu- coloration with circular hypopigmented follicu- mulative and intermittent sun exposure, with lar openings, called pseudo-network (like in history of sunburns in childhood and with cuta- seborrhoeic keratoses) [4]. neous signs of photodamage. In younger patients they are commonly numerous on face and shoul- ders, whereas in older subjects they appear on V.3.3.4 Relevant Clinical Differential the face, the backs of the hands and forearms. Diagnosis On the face lentigo maligna may be clinically V.3.3.3 Dermoscopic Criteria mistaken for actinic lentigines [5]. Sometimes lentigo maligna and actinic lentigo may have On dermoscopy, actinic lentigo appears with a clinically the same characteristics: regular and homogeneous pattern and coloration is largely homogeneous appearance and small size, lack- uniform (brown/tan; Fig. V.3.6). Commonly ing the ABCD signs of malignancy. All these le- they have a particular “moth-eaten” or “jelly- sions have been shown to benefit from the use of 294 P. Carli, C. Salvini

dermoscopy [6]. Dermoscopy discovers the real References nature of the lesions, revealing the presence of criteria diagnostic for actinic lentigo/early seb- 1. Argenziano G, Soyer HP, Giorgi V de et al. (2000) orrhoeic keratoses, or for early-stage lentigo Atlante interattivo di dermatoscopia. Edra Medical maligna (see Chap. IV.7). Publishing and New Media, Italy CD-ROM 2. Bolognia JL (1992) Reticulated black solar lentigo (“ink spot” lentigo). Arch Dermatol 128: 934–940 3. Argenziano G (2004) Dermoscopy of melanocytic V.3.3.5 Histopathology hyperplasias. Subpatterns of lentigines (ink spot). Arch Dermatol 140:776 There is a linear increase of melanocytes at the 4. Gasparini S, Giovene GL, Ferranti G (2003) Trattato dermo-epidermal junction, but no cytological di dermatoscopia. Sprinter-Verlag, Berlin Heidelberg atypia is present. There is frequently associated New York 5. Stante M, Giorgi V de, Stanganelli I et al. (2005) Der- solar elastosis and there may be slight hyper- moscopy for early detection of facial lentigo maligna. keratosis. The epidermis appears with extension Br J Dermatol 152:361–364 of the rete ridges to form bud-like processes ex- 6. Moreno-Ramirez D, Ferrandiz L, Camacho FM panding into the papillary dermis. (2005) Are the ABCD signs useful for the management of solar lentigo? Br J Dermatol 153: 1083–1084

V.3.3.6 Management Like the other lentigines, these lesions are benign and, for this reason, they do not need treatment. If a patient requires treatment for aesthetic reasons, either laser therapy or cryotherapy may be effective.

C Core Messages

■ Lentigines are persistently present macular increases in melanin pigmentation of the skin. ■ Lentigo simplex appears dermoscopically with a brown or brown-to-black network with a thin pattern and uniformly arranged stitches. ■ Ink-spot lentigo can clinically give the impression of being melanoma. The typical dermoscopic features of a prominent black-to-brown broken-up network allow to rule out melanoma. V.3 ■ Actinic lentigo usually has a homoge- neus dermoscopic pattern and a “moth- eaten” or “jelly-like” edge. ■ Lentigines are completely benign and do not need to be excised.